Transportation system and vehicles for the system

ABSTRACT

A transportation system having a roadway and vehicles movable over the roadway, the vehicles being levitated over the roadway by air cushion or magnetic means and the vehicles and the roadway having cooperable magnetic means for maintaining the vehicles properly aligned relative to the roadway. A vehicle movable over a roadway provided with ferromagnetic side rails, the vehicle having selectively energizable electromagnet assemblies at its sides cooperable with the ferromagnetic side rails for maintaining the vehicle in proper longitudinal alignment with the roadway during its movement thereover.

United States Patent [191 Goodnight et al.

[ 1 Jan. 21, 1975 TRANSPORTATION SYSTEM AND VEHICLES FOR THE SYSTEM [75] Inventors: Fred H. Goodnight, Dallas; George E. Walters, Arlington; John P. Ward, Dallas, all of Tcx.

[73] Assignee: LTV Aerospace Corporation, Dallas.

Tex.

22 Filed: Dec. 27, 1972 21 Appl. No.: 318,948

[52] U.S. Cl. 104/148 MS, 104/130, 104/105, 104/23 FS [51] Int. C1. B611) 13/00 [58] Field of Search 104/130, 105, 23 PS, 134, 104/148 LM, 148 MS [56] References Cited UNITED STATES PATENTS 2,996,267 8/1961 Warren 244/75 A 3,643,600 2/1972 Berlin t t v 104/130 3,680,488 8/1972 Donlon 104/130 3,702,099 11/1972 Ricaud 4, 104/105 3,763,788 10/1973 Pougue 104/1411 MS FOREIGN PATENTS OR APPLICATIONS 707,032 6/1941 Germany a 104/148 MS Primary Iixaminer-Lloyd L. King Assistant ExaminerD W. Keen Attorney, Agent. or Ft'rm-Wa1ter J, Jagmin; James M. Cate; H. C. Goldwirc 13 Claims, 13 Drawing Figures TRANSPORTATION SYSTEM AND VEHICLES FOR THE SYSTEM This invention relates to transportation systems and vehicles usable in such transportation systems.

An object of this invention is to provide a new and improved transportation system and a new and improved vehicle usable in the transportation system.

Some transporation systems have roadways over which vehicles are levitated, as by air cushion or magnetic repulsion means, and are propelled over the roadway by suitable drive means, such as linear induction motors. In such systems it is necessary that the vehicles and the roadway be provided with cooperable guide means for maintaining the vehicles in proper lateral alignment relative to the roadway. Such guide means should preferably operate with a minimum expenditure of energy and a minimum restraint or drag on the forward movement of the vehicle and provide forces tending to move the vehicle back into proper alignment which vary not only with the degree of displacement of the vehicle from proper alignment, but also with the rate of such displacement in order to prevent excessive lateral displacement of the vehicle relative to the vehicle. Such guide means should also permit switching of the vehicle from one section or main line of the roadway to another or branch line thereof.

Accordingly, it is an object of this invention to provide a new and improved system having a roadway and vehicles movable thereover wherein the roadway and the vehicles are provided with cooperable guide means for maintaining the vehicles in properly aligned relationship with the roadway.

Another object is to provide a new and improved transportation system wherein the guide means is energized only at the times the vehicle tends to move out or is out of proper transverse or lateral alignment with the roadway.

Still another object is to provide a transportation system provided with a roadway having a planar top surface and side ferromagnetic guide rails along the sides of the roadway, and a vehicle having electromagnet means which are cooperable with the guide rails and are energized when the vehicle tends to move out of alignment with the roadway to provided electromagnetic forces between the magnet and the guide rails to maintain in proper longitudinal alignment with the roadway.

Still another object is to provide a transportation system wherein the roadway may have a main section and branch sections extending angularly from the main section and wherein the electromagnetic means are individually movable between lower operative positions in alignment with the guide rails and upper inoperative positions wherein they are positioned above the roadway to permit movement of the vehicle from one section of the roadway to another.

An important object is to provide a new and improved vehicle movable over a roadway having ferromagnetic guide rails along its side wherein the vehicle has selectively energizable electromagnetic means cooperable with the guide rails for holding the vehicle in properly aligned relationship relative to the roadway.

Another object is to provide a vehicle, of the type described, having control means for controlling energization of the electromagnetic means to cause them to be energized only when the vehicle tends to move out of proper relationship to the roadway.

Still another object is to provide a vehicle, of the type described, wherein the control means varies the energization of the electromagnetic means not only in accordance with the degree of displacement of the vehicle from proper relationship with the roadway but also in accordance with the rate of displacement to whereby the degree of displacement of the vehicle is minimized even under conditions of imposition of sudden extreme transverse forces on the vehicle.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of transportation systems constructed in accordance with the invention and reference to the accompanying drawings thereof, wherein;

FIG. I is a top fragmentary view of a roadway of the vehicle system embodying the invention;

FIGS. 2, 3, 4 and 5 are sectional views taken on lines 22, 3-3, 4-4 and 5-5, respectively, of FIG. 1;

FIG. 6 is a top schemtaic view of a vehicle of the transportation system embodying the invention;

FIG. 7 is a perspective view of a core of an electromagnetic assembly of the vehicle;

FIG. 8 is a perspective view of an electromagnetic assembly of the vehicle embodying the invention;

FIG. 9 is a fragmentary top view showing the means by which the electromagnetic assembly of the vehicle is movable vertically between operative and inoperative positions;

FIG. 10 is a side view of the assembly illustrated in FIG. 9;

FIG. 11 is a partly schematic vertical sectional view showing a vehicle of the transportation system on the roadway thereof;

FIG. 12 is a block view illustrating the control means for a pair of electromagnetic assemblies of the vehicle; and,

FIG. 13 is a partly schematic view of the control circuit of the vehicle.

Referring now to the drawing, the transportation system 20 includes a roadway 21 which may have a main section 22 and one or more branch sections 23. The roadway may be formed of concrete bed 24 having a top planar surface 25 over which vehicles V may move. The vehicles during movement are levitated above the planar surface 25 of the roadway by any suitable means, such as by compressed air which is forced into the downwardly opening air cushion pans 28 and 28a which are secured to the vehicle body by suitable pivot means 29 and 29a. The compressed air is transmitted to the downwardly opening pans through suitable flexible conduits 30 in a well known manner. The exact means by which the vehicles are levitated over the roadway, not being a part of this invention and being well known, will not be described further.

The vehicles may be propelled over the roadway by any suitable drive means such as a linear induction motor having primaries 31 embedded in the roadway and secondaries 32 connected to the vehicles.

Each vehicle is guided and stabilized during its high velocity movement over the roadway by guide means which include electromagnet assemblies 33, 34, 35a and 35b which are mounted at the four corners of each lift pan and which cooperate with the ferromagnetic side rails 35 and 36 which are rigidly secured to the roadway bed 24 at its sides.

Each of the electromagnet assemblies includes a core 40, substantially I-shaped in cross section, which may be formed of laminated steel or iron. The core has top and bottom inner horizontal sections 41 and 42, top and bottom outer horizontal sections 43 and 44 and a central vertical connector section 45. An inner coil 46 is disposed about the top inner section 41 and an outer coil 47 is disposed about the top outer core section 43.

Each electrogmagnet assembly includes a suitable rectangular housing 50 in which the electrogmagnet formed by the cores and coils are disposed. The inner portions of the sections 41 and 42 extend outwardly of the inner side of the housing while the outer portions of the outer sections 43 and 44 extend outwardly of the opposite outer side of the housing for a purpose to be described below. It will be apparent that when the coil 46 is energized with direct current, the inner horizontal portions 41 and 42 and the connector portion 45 of the core have a magnetic flux induced therein and constitute a horseshoe magnet. For example, the top portion 41 constitutes the south pole of the magnet and the bot tom portion 42 constitutes the north pole of the magnet. As a result, the electromagnet assembly, when the coil 46 is energized, is attracted to a ferromagnetic side rail which its horizontal portions 41 and 42 face. Similarly, when the coil 47 is energized, the top and bottom outer portions 43 and 44 constitute the south and nother poles and the electromagnet assembly will be attracted toward an adjacent outer ferromagnetic rail such as the rails 53, S4, 105 and 106. The outer rails are disposed at locations of shunting or switching of a vehicle from the main track section to a side or branch section 23 as will be explained below.

Each of the magnet assemblies 50 is mounted on an air pan, such as the air pan 28, by means of cranks 57 and 58, FIGS. 9 and 10. The crank 57 has an arm 59 which is pivotally mounted at its lower end to a bracket 60 for pivotal movement about a shaft 61. The bracket 60 may be secured to the top surface of the air pan by any suitable means, such as bolts, welding or the like.

The other arm 62 of the crank 57 is rigidly secured at its upper end to the upper end of the arm 59 by a pin 63. The lower end of the crank arm 62 is pivotally secured to the housing 50 by means of the lugs 64 which extend upwardly from the upper end of the top surface of the housing 50 and a shaft 65.

The crank arm 59 at its upper end is provided with a pair of upstanding lugs 66 between which extends the outer end of the piston rod 68 of a hydraulic or pneumatic ram 70 and is pivotally connected thereto by a pin or a shaft 71. The cylinder 72 of the hydraulic ram, at its end opposite remote from the crank 57, is provided with a lug 74 which extends into the slot 75 of a bracket 76 and is pivotally secured thereto by pivot pin or shaft 77. The bracket 76 is provided at its lower end with a foot 79 which rests on the top surface of the air pan and is secured thereto in any suitable manner. The piston rod 68 extends from the piston 80 of the ram which is reciprocable in the cylinder 72.

The piston moves to extend the piston rod 68 when fluid under pressure is admitted to its inlet 8! while fluid is allowed to exhaust from its other end through the fitting 82. Conversely, the piston rod is moved to its retracted position when fluid under pressure is admitted into the cylinder through the fitting 82 and allowed to exhaust from the fitting 81.

The crank 58 includes an arm 85 which is pivotally connected at its lower end to the air pan by a shaft 86 which is rotatably secured to a pillow block 87 mounted on the air pan. The other arm 88 of the crank 58 is rigidly secured to the top end of the arm 85 by a pin or rod 89. The lower end of the crank arm 88 extends between a pair of upstanding lugs 91 of the housing and is pivotably secured thereto by a shaft or pivot pin 92. The various connections of the cranks to the air pan and to the housing permit vertical movement ofthe housing relative to the air pan from a lower operative position such as that in which is disposed the magnet assembly 36 as seen in FIG. 11, and an upper inoperative position, such as that in which is disposed the electromagnet assembly 35, as seen in FIG. 11.

Each of the electromagnet assemblies also includes inner and outer sensors 95 and 96 which may be mounted on the core as illustrated in FIG. 7, or on the housing 50, for sensing the air gap or distance between the electromagnetic assembly and its adjacent inner or outer guide rail of the roadway and providing voltages which vary in accordance with the air gap or distance between the electromagnetic assemblies and the side and outer rails of the roadway as will be explained in greater detail below.

Referring now to FIGS. 1 through 5 of the drawings, the roadway 21 in addition to the side ferromagnetic guide rails 35 and 36, at location of juncture of a branch section 23 ofthe roadway with the main section 22, is provided with the outer guide rails 53 and 54. The guide rail 53 extends along one side of the roadbed parallel to and spaced from the side guide rail 35. The guide rail 54 extends parallel to and spaced from the guide rail 36 which extends along one side of the main section and then curves to become one side guide rail of the branch section 23 of the roadway. A side guide rail 36a extends from the juncture of the main section 23 and a guide rail 104 extends along the other side of the roadbed of the branch section 23. Outer guide rails I05 and I06 extend from the juncture of the branch section with the main section of the roadbed parallel to and spaced from the side rails 36a and 104 at the location of the branch section 23.

The outer guide rails 53, 54, 105 and 106 may be secured to outer concrete side walls 11], 112, 113 and 114, respectively.

The rails 35, 36, 36a and I04 are provided with outwardly extending horizontal top flanges I15, 116, [16a and 117, respectively, while the outer guide rails 53, S4, 105 and 106 are provided with inwardly extending flanges 118, 119, 120 and 121, respectively.

The top flange 115 of the guide rail 35 has a notch 123 to permit upward movement of the right side electromagnet assemblies 34 and 35a to a position above the roadway in the event the vehicle is to move from the main section of the roadway onto its branch section 23. Similarly, the top flange 116 of the side guide rail 36 has a section removed, or a notch 124, to permit upward movement of the left side electromagnet assemblies 33 and 35b to a position above the roadway in event the vehicle is to continue to move along the main section 22 of the roadway and not be shunted or switched onto the branch section 23. The guide rail 116a similarly has a section removed, as at 125, to per mit downward movement of the left side electromagnet assemblies 33 and 35b downwardly to operative position relative to the guide rail 36a as the vehicle moves past the juncture of the branch section of the roadway with the main section. Similarly, the flange 1 17 of guide rail 104 of the branch section 23 of the roadway has the portion removed, as at 126, to permit downward movement of the right side electromagnetic assemblies 34 and 35a into operative relation with the guide rail 104 as the vehicle moves from the main section of the roadway onto its branch section.

It will be apparent that as a vehicle V moves to the left along the main section 112 of the roadway and approaches its juncture with the branch section, if the vehicle is to continue moving to the left on the main section of the roadway, the left electromagnetic assemblies 33 and 35b are moved upwardly, as by causing compressed air to be introduced into the cylinders of their pneumatic rams 70 through the fittings 82 while the opposite fittings 81 are vented at the time the electromagnet assemblies on each air pan move into align ment with the gap or notch 124 in the top flange 16 of the guide rail 36. As a result, the left side assemblies 33 and 35b are now in inoperative position above the roadway. Only the right side assemblies 34 and 350 are now operative. The inner coil 46 of each assembly 34 and 35a is energized if the vehicle tends to move transversely to the right relative to the roadway and the outer coils 47 of the assemblies 34 and 350 are energized if the vehicle tends to move transversely to the left relative to the roadway. After the electromagnetic assemblies 34 and 35a move past the location of juncture of the branch section of the roadway with its main section, the left side assemblies 33 and 35b are lowered through the notch 125 to operative relationship with the guide rail 36a and the inner coils of the right side assemblies and the inner coils of the left side assemblies will now be energized as required to maintain the vehicle in proper transverse relationship to the main section of the roadway as the vehicle moves past the juncture of the branch section with the main section.

Conversely, if the vehicle moving on the main section is to move, or be shunted or switched, onto the branch section 23, the right side electromagnetic assemblies 34 and 35a are moved upwardly as they move into alignment with the notch 123 of the top flange 115. The inner and outer coils of the left side assemblies 33 and 35b are then operative, to maintain the vehicle in proper position on the roadway and to guide it onto the branch section 23. As the vehicle moves onto the branch section, the right side ferromagnetic assemblies are lowered as they move into alignment with the notch 126 in the flange 117 and thereafter only the inner coils of the right and left side ferromagnetic assemblies are operative to guide the vehicle along the branch section 23.

Due to the location of the ferromagnetic assemblies at the four comers of the air pans or support means 28 and 28a of the vehicle, the radius of turning movement of the vehicle may be made relatively small so that the roadway may curve as required either along the main section or at the locations of the junctures of branch sections with the main section.

Referring now to FIG. 12 of the drawings, the control means 129 for controlling operation of each pair of transversely aligned electromagnetic assemblies such as the left and right electromagnetic assemblies, 33 and 34, includes a switch 130 having four movable contacts BI, [32, I33 and I34 and an operator and indicator handle 135. The switch 130 controls the operation of the inner and outer coils of the two transversely aligned magnet assemblies 33 and 34 and of the air gap sensors 95 and 96 thereof. The air gap sensors may be of any suitable type such as the commerically available Kaman Sciences KD-2300-l0CU-Multi-VIT transducer. Each air gap sensors provides an output voltage which varies in accordance with the air gap between the sensor and its adjacent ferromagnetic rail.

When the vehicle V is travelling along a straight section of the roadway, the switch contacts are in the positions illustrated in FIG. 12 and the inner air gap sensors of the two magnetic assemblies are in operative condition, their outputs being transmitted to a control circuit 136 which controls the energization of the inner coils 46 of the two magnetic assemblies. One side ofthe output circuit of the sensor 95 of the electromagnetic assembly 33 is now connected to the control circuit 136 through a conductor 138, the stationary contact 164 of the switch, a conductor 165, the movable contact 134, and the conductor 140. The opposite side of the output circuit of the sensor 95 is connected to the control circuit through a conductor 142, ground, and the conductor 155. At this time the output of the sensor 95 of the right side assembly 34 is also transmitted to the control circuit 136 through a conductor 144, the stationary contact of the switch, the movable contact 133 and a conductor 146. The control circuit 135, as will be explained below, selectively energizes the inner coils 46 of the two electromagnetic assemblies 33 and 34 depending on the magnitudes of the output of the control signals of the two inner gap sensors 95 of the two assemblies, If, for example, a vehicle V moving along the main section of the roadway is properly positioned relative to the roadway, the outputs of the two inner sensors 95 of the electromagnetic assemblies 33 and 34 are equal. if the vehicle tends to move to the right, the output of the sensor 95 of the as sembly 34 will tend to increase as its distance from the ferromagnetic side rail 35 tends to increase, while the output signal of the sensor 95 of the assembly 33 will tend to decrease as the gap between it and the side ferromagnetic guide rail 36 tends to decrease. The control circuit 136 will now cause the inner coil 46 of the right side electromagnetic assembly 34 to be energized with direct current which will vary as will be explained below with the rate of lateral movement of the sensors 95 of the left and right side assemblies away and towards, respectively, the side rails 35 and 36 and also with the distances between the sensor and the side rails. The control circuit will then connect the coil 46 of the assembly 34 across an input circuit of direct current 150, one side of the coil 46 of the assembly 34 then being connected to one side of the direct current power input circuit through a conductor [51, the control circuit 136, a conductor [52, the movable contact 131, the stationary contact 152a of the switch and the conductor 153. The other side of the coil 46 of the assembly 34 is connected to the other side of the power input circuit through the conductor 154 and ground. The inner coil 46 of the left side magnetic assembly 33 will of course remain de-energized.

Conversely when the vehicle at the location of the electromagnetic assemblies 33 and 34 tends to move to the left, the inner sensor 95 of the right side assembly 34 tends to approach the guard rail 35 while the sensor 95 of the left side assembly 33 tends to move away from the side rail 36. As a result, the control circuit 136 will now energize the inner coil 46 of the left side electromagnetic assembly 33 while leaving the inner coil of the opposite right side assembly 34 de-energized, the

coil 46 of the assembly 33 being connectible to the input circuit 150 through the control circuit 136, a conductor 158, the contacts 132 and 159a of the switch, the conductors 159 and 160, and ground. The force of a magnetic attraction between the magnetic assembly 33 and the side rail will now tend to move the vehicle back toward the right to maintain it in proper relationship to the roadway.

lf the vehicle which is moving to the left, as seen in FIG. 5, is to be switched or shunted onto the branch section 23 when each pair of transversely aligned magnetic assemblies, such as the pair 33 and 34, move into alignment with the gaps 124 and 123 in the flanges 116 and 115, respectively, the right side assembly is moved upwardly, as explained above, above the side rail 35 and the roadbed. Simultaneously, the switch contacts are moved upwardly to positions wherein the contact 131 engages a stationary contact 161, the contact 132 engages a stationary contact 162, the contact 133 engages a stationary contact 162, the contact 133 engages the contact 163, and the contact 134 engages the contact 164. The sensors 95 and 96 of the right side assembly 34 are now in inoperative condition disconnected from the control circuit 136. The sensor 95 of the left side assembly 33 will now remain in operative condition since the contact 134 is now in engagement with the contact 164. The inner coil 46 of the assembly 33 will also remain connected to the control circuit 136 since the stationary contact 162 is connected to the contact 1590 by the conductor 163.

One side of the outer gap sensor 96 of the assembly 33 is now connected to the control circuit 136 through the conductor 170, a stationary contact 163 and the movable contact 133 of the switch, and the conductor 146 while its other side is connected to the control circuit through the conductor 171, ground and the con ductor 155. One side of the outer coil 47 of the left side assembly 33 is now connected to one side of the power input circuit 150 through a conductor 172, the contacts 161 and 131 of the switch and the conductor 152. The opposite side of the outer coil 47 of the assembly 33 is connected to the other side of the power input circuit through a conductor 174, ground and the conductor 155.

The left side electromagnetic assembly 33 will then cooperate with the side rails 35 and 54 to guide the vehicle from the main section of the roadway to its branch section 23, its outer coil 47 being energized to provide a magnetic attraction force between the assembly 33 and the guide rail 54 if the vehicle tends to move to the right from its proper transverse position relative to the roadway and the coil 46 being energized if the vehicle tends to move to the left from its proper position to provide a magnetic attraction force between the assembly 33 and the guide rail 36.

As the vehicle moves onto the branch section 23 of the roadway and the right side assembly 34 moves into alignment with the gap 126 of the flange 117, the assembly 34 is moved downwardly and contacts of the switch 130 are moved back to the position illustrated in FIG. 12 so that the assemblies 33 and 34 will now cooperate with the side rails 36 and 104 to guide the vehicle as it moves over the branch section 23.

Conversely, if the vehicle is to continue to move on the main section 22 of the roadway past the juncture thereof with the branch section 23, as the left side magnetic assembly 33 moves into alignment with the notch 124, it is moved upwardly, as explained above. and the movable contacts 131-134 of the switch 130 are moved downwardly to engage the stationary contacts 181, 182, 183 and 184, respectively, thereof, Such movement of the contacts 131-134 now prevents energization of both coils 46 and 47 of the left side assembly 33 and also disconnects its sensors and 96 from the control circuit 136. Movement of the contact 131 into engagement with the contact 181 now permits the energization of the inner coil 46 of the assembly 34, the contact 131 now connecting one side of the coil 46 of the assembly 34 to the conductor 152 through the conductors 153 and 186. Simultaneously one side of the outer coil 47 of the assembly 34 is connected to the conductor 158 through the conductor 189, the contacts 182 and 132 of the switch.

The sensor 95 of the assembly 34 will now be connected to the control circuit 136 by the conductors 144 and 191, the switch contacts 183 and 133, and the conductor 146 and the sensor 96 of this assembly will be connected to the control circuit through the conductor 193, the contacts 184 and 134 and the conductor 140.

The right side electromagnetic assembly 34 will therefore now cooperate with the rails 35 and 53 to guide movement of the vehicle over the roadway past the juncture therewith of the roadway branch section 23. When the left side magnetic assembly 33 moves into position past the juncture of the roadways branch and main sections, it is lowered through the notch of the flange 1160 of the side rail 36a and the switch contacts are moved again to the position illustrated in FIG. 12 and the inner coils 46 of the assemblies will now cooperate with the rails 35 and 36a to guide continued movement of the vehicle over the portion of the main section of the roadway to the left of its juncture with the branch section 23.

The control circuit 136, as illustrated in FIG. 13, includes a summer 201 which sums the opposite polarity voltages which are supplied thereto by each particular pair of the air gap sensors which are connected to the conductors and 146 at a particular time.

A compensation circuit 205 is provided to produce an output signal which varies not only with the distances or air gaps between the air gap sensors and their associated guide rails but also with the rate of change of such distances. The compensation circuit 205 includes a differential amplifier 206 having a power input circuit 207 and an input terminal 208 to which the out put of the summer 201 is transmitted through a pair of resistances 209 and 210 connected in series between the summer and the amplifier input terminal 208 by the conductors 211, 212, and 213. A capacitor 215 is connected across the resistance 209, one side thereof being connected to the conductor 211 by a conductor 216 and its other side being connected to the conductor 212 by a conductor 217. One side of a resistance 218 is connected to the common connection 220 of capacitor 215 and the resistances 209 and 210 by a conductor 221 and its other side is connected to ground through a conductor 222.

The amplifier 206 has a feedback network 225 which serves as a filter to decrease noise or spurious frequencies connected between its output terminal or conductor 226 and its input terminal 227 which includes a resistance 229 connected between the conductor 226 and the input terminal 227 by the conductors 231, 232, 234 and 235. A capacitor 237 is connected across the output and input terminals 226 and 227 of the amplifier, and also across the resistance 229, by the conductors 231 and 234. The second input terminal 227 of the differential amplifier 206 is also connected to ground through the conductor 235, a resistance 240 and a conductor 241.

The resistance 209 is substantially greater than the resistances 210 and 218 so that if the output of the summer is, for example, a positive voltage of a given value and is constant, since the resistances 209 and 218 act as a voltage divider network, the voltage at the common junction 220 of the resistances 209 and 210 will now be smaller than the output voltage of the summer 201. [f the vehicle is being displaced laterally at a rapid rate, the output voltage will be transmitted directly through the capacitor 215 to the common connection 220 so that the input voltage at the input terminal 208 will now be greater for given instant air gap distances between the sensors 95 and their associated guide rails than that which would ordinarily be present at the common connection 220 at such distances if the sensors were not moving rapidly. As a result, the output of the differential amplifier will be greater for a given air gap between these sensors and their associated guide rails if the vehicle is being displaced at a lower rate or indeed if the air gap distances were constant as when the vehicle is slightly displaced laterally relative to the guide rails. This latter condition could occur in event of a constant side wind load on the vehicle. The output of the differential amplifier is transmitted to an input terminal 239 of a square root circuit 240 whose output voltage varies as the square root of the signal or input voltage transmitted to its input terminal 239. The output of the square root circuit 240 is transmitted through a conductor 24] to the input terminal 242 of a push-pull amplifier 244, which may be of any suitable commercially available type, such as a Westamp amplifier Model No. A653-286-BXX. The square root circuit is employed because the magnetic force produced by each coil varies as the square of the value of the current flowing therethrough.

Assuming now that the vehicle is on the main section 22 of the roadway and is in properly aligned position on the roadway, the outputs of the air gap sensors 95 of the left and right magnetic assemblies 33 and 34 which are being transmitted to the opposite sides of the summer 201 are equal. As a result, the output of the summer 201 is zero and the push-pull amplifier 244 is not energized and therefore neither of the coils 46 of the assemblies 33 and 34 is energized. The capacitor 215 of the compensating circuit is now in discharged condition, its opposite sides having the same potential since any charge on the capacitor 215 has been discharged to ground through the discharge resistance 218.

If the vehicle should now tend to move or be displaced very slowly to the left relative to the roadway, the voltage output of the air gap sensor 95 of the right side assembly 34 will decrease as it approaches the side rail 35 while the voltage output of the air gap sensor 95 of the left side assembly will increase as the gap between it and the side rail 36 increases. The summer 20] will now provide a signal of slowly increasing voltage of one polarity, for example, negative. As a result the capaeitor 2l5 will not be effective and the rate of change of the control voltage now being supplied to the input terminal 208 of the differential amplifier will also be slow and will vary with the distances between the sensors and the side rails. The voltage signal produced by the summer 20] and transmitted to the push-pull amplifier 244 will now cause the amplifier 244 to transmit a direct current through the conductor 158 to the coil 46 of the left side assembly so that the force of mag netic attraction between left side electromagnetic assembly and the rail 36 will now tend to move the left side assembly, and therefore the vehicle, to the right back towards properly aligned relationship with the roadway. At such time, of course, the output of the summer 20] would decrease to zero. No current is transmitted to the conductor 152, and therefore to the coil 46 of the right side assembly, when current is supplied to the conductor 158.

If the rate oflateral displacement of the vehicle to the left is great, the capacitor 215 will of course transmit a pulse of relatively high voltage to the common connection 220, greater than that which would be present at the common connection 220 for a given displacement of the air gap sensors relative to the guide rails 35 and 36 under static conditions of displacement. As a result, the energization of the coil 46 of the left side assembly 34 is relatively great and the force of mag netic attraction thereof with the guide rail 36 will be great and will arrest such movement of the vehicle and move it back to its proper position on the roadway.

It will be apparent that if the vehicle tends to move to the right relative to the roadway, the sensor 95 of the assembly 33 will approach the rail 36 while the sensor of the right side assembly will move away from the rail 35. As a result, the voltage input to the conductor 40 will be smaller than the voltage input to the conductor 146 and a direct current of negative polarity produced by the summer, which varies in accordance with the degree and rate of displacement of the vehicle will cause the amplifier 244 to energize the coil 46 of the right side assembly 34, through the conductor [52, and move the vehicle back to the left.

It will now be apparent that each transversely aligned pair of electromagnetic assemblies, such as the pairs of assemblies 33 and 34 and 35a and 35b, is provided with a separate control means [30 and that the electromagnetic assemblies of each such pair cooperate to exert lateral forces on the vehicle when the vehicle is dis played from proper position relative to the roadway to move the vehicle back to proper position.

It will further be seen that since the coils of the electromagnetic assemblies are energized only when the ve hicle tends to move out of proper position relative to the roadway, minimum amounts of energy are expended and the drag" or force tending to oppose forward movement of the vehicle, due to eddy currents induced in the ferromagnetic rails is minimized.

While a particular embodiment of the invention has been illustrated and described, various changes in structure may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed and desired to be secured by Letters Patent is:

l. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, each said electromagnetic means when energized being attracted to an adjacent guide rail or said roadway; sensor means operatively associated with each of said electromagnetic means and a guide rail adjacent said electromagnetic means for providing control signals which vary in accordance with the distance of the electromagnetic means from the adjacent side rail; and control means responsive to said control signals for controlling energization of said electromagnetic means to cause said electromagnetic means to exert lateral forces on said vehicle when said vehicle tends to move out of properly aligned transverse relationship to said roadway to cause said vehicle to maintain a properly aligned relationship with the roadway, said control means including means for varying the degree of energization of said electromagnetic means in accordance with the rate of change of said control signals.

2. The system of claim 1, and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.

3. The system of claim 2, wherein said vehicle is provided with a pair of longitudinally spaced support means rotatable about vertical axes, said electromagnetic means being mounted on said support means.

4. The system of claim 3, wherein each of said support means has a pair of front and a pair of rear transversely aligned electromagnetic means.

5. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, said roadway including at least one outer guide rail extending parallel to and spaced outwardly of one of said guide rails, one of said electromagnetic means being movable between said outer guide rail and said one of said guide rails and comprising a pair of coils selectively energizable for providing magnetic forces selectively attracting said electromagnetic means to said outer guide rail and said one of said guide rails.

6. The transportation system of claim 5, wherein one of said electromagnetic means includes a core having a pari of inner horizontal spaced portions extending inwardly toward said one of said guide rails and a pair of outer horizontal spaced portions extending outwardly toward said outer guide rail and a vertical connecting portion connecting said pairs of portions; one of said coils being positioned about one of said inner portions and the other of said coils being positioned about one of said outer portions.

7. In a vehicle over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guides means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship to and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; sensor means opera tively associated with each of said electromagnetic means for providing a signal which varies in accordance with the distance between each electromagnetic means and an adjacent guide rail of a roadway; and control means responsive to said control signals for varying energization of each of said electromagnetic means to vary the force with which each electromagnetic means is attracted to its adjacent side rail when the vehicle is displaced from a predetermined relationship relative to the roadway, said control means including means for varying the degree of energization of said electromagnetic means in accordance with the rate of change of said control signals.

8. The guide means of claim 7, and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.

9. In a vehicle movable over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guide means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship to and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; said roadway including at least one outer guide rail extending parallel to and spaced outwardly of one of said guide rails, one of said electromagnetic means being movable between said outer guide rail and said one of said guide rails and comprising a pair of coils selectively energizable for providing magnetic forces selectively attracting said electromagnetic means to said outer guide rail and said one of said guide rails.

10. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, each said electromagnetic means when energized being attracted to an adjacent guide rail of said roadway, sensor means operatively associated with each of said electromagnetic means and a guide rail adjacent said electromagnetic means for providing control signals which vary in accordance with the distance of the electromagnetic means from the adjacent side rail; control means responsive to said control signals for controlling energization of said electromagnetic means to cause said electromagnetic means to exert lateral forces on said vehicle when said vehicle tends to move out of properly aligned transverse relationship to said roadway to cause said vehicle to maintain a properly aligned relationship with the roadway; and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.

11. The system of claim 10, wherein said vehicle is provided with a pair of longitudinally spaced support means rotatable about vertical axes. said electromagnetic means being mountd on said support means.

12. The system of claim 11, wherein each of said support means has a pair of front and a pair of rear transversely aligned electromagnetic means.

13. In a vehicle movable over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guide means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship to and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; sensor means operatively associated with each of said electromagnetic means for providing a signal which varies in accordance with the distance between each electromagnetic means and an adjacent guide rail of a roadway; and control means responsive to said control signals for varying energization of each of said electromagnetic means to vary the force with which each electromagnetic means is attracted to its adjacent side rail when the vehicle is displaced from a predetermined relationship relative to the roadway, and means operatively as sociated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section. 

1. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, each said electromagnetic means when energized being attracted to an adjacent guide rail or said roadway; sensor means operatively associated with each of said electromagnetic means and a guide rail adjacent said electromagnetic means for providing control signals which vary in accordance with the distance of the electromagnetic means from the adjacent side rail; and control means responsive to said control signals for controlling energization of said electromagnetic means to cause said electromagnetic means to exert lateral forces on said vehicle when said vehicle tends to move out of properly aligned transverse relationship to said roadway to cause said vehicle to maintain a properly aligned relationship with the roadway, said control means including means for varying the degree of energization of said electromagnetic means in accordance with the rate of change of said control signals.
 2. The system of claim 1, and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.
 3. The system of claim 2, wherein said vehicle is provided with a pair of longitudinally spaced support means rotatable about vertical axes, said electromagnetic means being mounted on said support means.
 4. The system of claim 3, wherein each of said support means has a pair of front and a pair of rear transversely aligned electromagnetic means.
 5. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, said roadway including at least one outer guide rail extending parallel to and spaced outwardly of one of said guide rails, one of said electromagnetic means being movable between said outer guide rail and said one of said guide rails and comprising a pair of coils selectively energizable for providing magnetic forces selectively attracting said electromagnetic means to said outer guide rail and said one of said guide rails.
 6. The transportation system of claim 5, wherein one of said electromagnetic means includes a core having a pari of inner horizontal spaced portions extending inwardly toward said one of said guide rails and a pair of outer horizontal spaced portions extending outwardly toward said outer guide rail and a vertical connecting portion connecting said pairs of portions; one of said coils being positioned about one of said inner portions and the other of said coils being positioned about one of said outer portions.
 7. In a vehicle over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guides means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship To and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; sensor means operatively associated with each of said electromagnetic means for providing a signal which varies in accordance with the distance between each electromagnetic means and an adjacent guide rail of a roadway; and control means responsive to said control signals for varying energization of each of said electromagnetic means to vary the force with which each electromagnetic means is attracted to its adjacent side rail when the vehicle is displaced from a predetermined relationship relative to the roadway, said control means including means for varying the degree of energization of said electromagnetic means in accordance with the rate of change of said control signals.
 8. The guide means of claim 7, and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.
 9. In a vehicle movable over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guide means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship to and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; said roadway including at least one outer guide rail extending parallel to and spaced outwardly of one of said guide rails, one of said electromagnetic means being movable between said outer guide rail and said one of said guide rails and comprising a pair of coils selectively energizable for providing magnetic forces selectively attracting said electromagnetic means to said outer guide rail and said one of said guide rails.
 10. A transportation system including: roadway comprising of a bed over which vehicles are movable longitudinally in levitated position and a pair of magnetic side guide rails extending longitudinally along opposite sides of the roadway; and a vehicle movable over the roadway, said vehicle having electromagnetic means at each side thereof aligned transversely and cooperable with adjacent side rails thereof and selectively energizable when the vehicle tends to move out of proper alignment with the roadway for maintaining the vehicle in properly aligned transverse relationship over the roadway, each said electromagnetic means when energized being attracted to an adjacent guide rail of said roadway; sensor means operatively associated with each of said electromagnetic means and a guide rail adjacent said electromagnetic means for providing control signals which vary in accordance with the distance of the electromagnetic means from the adjacent side rail; control means responsive to said control signals for controlling energization of said electromagnetic means to cause said electromagnetic means to exert lateral forces on said vehicle when said vehicle tends to move out of properly aligned transverse relationship to said roadway to cause said vehicle to maintain a properly aligned relationship with the roadway; and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section.
 11. The system of claim 10, wherein said vehicle is provided with a pair of longitudinally spaced support means rotatable about vertical Axes, said electromagnetic means being mountd on said support means.
 12. The system of claim 11, wherein each of said support means has a pair of front and a pair of rear transversely aligned electromagnetic means.
 13. In a vehicle movable over a longitudinal roadway having parallel longitudinal ferromagnetic guide rails along opposite sides thereof; a guide means comprising a pair of transversely aligned and spaced electromagnetic means mounted on said vehicle movable in spaced relationship to and cooperable with said guide rails for exerting transverse forces on said vehicle when said vehicle tends to move out of proper alignment with said roadway for holding said vehicle in proper transverse alignment relative to the roadway; sensor means operatively associated with each of said electromagnetic means for providing a signal which varies in accordance with the distance between each electromagnetic means and an adjacent guide rail of a roadway; and control means responsive to said control signals for varying energization of each of said electromagnetic means to vary the force with which each electromagnetic means is attracted to its adjacent side rail when the vehicle is displaced from a predetermined relationship relative to the roadway, and means operatively associated with each of said electromagnetic means for selectively moving said electromagnetic means out of operative relationship with said side rail and above said roadway to permit movement of a vehicle from one section of the roadway to another section extending angularly relative to said one section. 